1. Field of the Invention
The present invention relates to an apparatus and method for cleaning a wafer used in the manufacture of a semiconductor device.
2. Description of the Related Art
Recently, numerous methods for cleaning a wafer using high frequency acoustic energy, such as megasonic energy, have been introduced. An apparatus for cleaning a semiconductor wafer using megasonic energy removes pollutants (e.g., particles) from a wafer surface by providing megasonic energy through the cleaning fluid. One example of an apparatus for cleaning a semiconductor wafer that uses high frequency acoustic energy is the GOLD FINGER cleaning apparatus introduced by Verteq, Inc., which is disclosed in U.S. Pat. No. 6,039,059 (issued on Mar. 21, 2000 to Mario E. Bran, et al.) and hereby incorporated by reference in its entirety. Although, the apparatus for cleaning a semiconductor wafer by providing megasonic energy effectively removes particles from a wafer surface, patterns formed on the wafer are sometimes damaged during the cleaning process. Damage to the patterns includes, for example, lifting of the patterns. In particular, patterns can be severely damaged on the edge of the wafer.
It is known that damage to the patterns occurs due to a concentration of megasonic energy or vibrational energy of fluids. As design rules required for a semiconductor device become more narrow, damage to the patterns can increase. For example, if a line width of the pattern is less than 0.12 μm, damage to the patterns due to the cleaning process can increase.